Surrender is a rule that lets a player give up half a bet instead of losing all of it. It appears in two quite different settings: blackjack and roulette.
In blackjack, surrender allows you to fold a weak starting hand and recover half your stake. You can only use it as your very first decision, after the opening two cards are dealt and before you hit, double, split or stand. Some versions offer late surrender, which becomes available only after the dealer has checked for a natural blackjack.
Roulette has its own version. Some double-zero tables apply a surrender rule to even-money outside bets: when the ball lands on 0 or 00, you lose only half of the stake instead of all of it.
Surrender as a selling point
Surrender lowers the house edge, so informed players look for it. State clearly in each table’s rules whether it is offered and in which form. On roulette, it plays a similar role to the en prison rule on single-zero wheels.